Along with development of digital home appliances such as personal computers, DVD drive recorders with a built-in hard disk drive, digital video cameras, portable digital music players, and portable telephones, hard disk drives (HDD) have been increasingly made smaller from 3.5 inches to 2.5 inches, 1.8 inches, 1.0 inch, and 0.85 inches, while their capacity has been increased. Therefore, there has been a strong demand for hard disk drive inner parts formed of a resin from the standpoint of a reduction in size and cost. For example, use of a polyoxymethylene resin (see WO03/055945, for example) or a polyphenylene sulfide resin (see JP-A-2003-335871, for example) has been proposed as a ramp material which is required to exhibit sliding properties with a metal.
These materials exhibit improved sliding properties, but exhibit insufficiently low outgassing properties. Low outgassing properties are very important properties for hard disk drive inner parts. Since the hard disk placement space has been reduced along with a trend toward a reduction in size, hard disk drive inner parts have been sought which exhibit more excellent low outgassing properties.
Examples of parts for which sliding properties are not required to a large extent that can be given are, a bracket, a latch, a comb, a spoiler, a bush, a mounting plate, a hook, and the like. A polyetherimide, a liquid crystal polyester, and a polycarbonate have been used for most of these parts. However, these materials do not exhibit a sufficient balance between low outgassing properties, cleanliness (absence of silicon, halogen, sulfur, and the like), cost, specific gravity, and water-absorbing properties.
Therefore, there has been a strong demand for hard disk drive inner parts formed of a resin that exhibit excellent low outgassing properties, are not contaminated with particulate and ions, and exhibit well-balanced heat resistance, cost, specific gravity, and water-absorbing properties.
A method has been proposed which improves the heat resistance and mechanical properties by alloying a polyphenylene ether resin with a liquid crystal polyester (see JP-A-2003-073560, for example). However, the document is silent about hard disk drive inner parts and outgassing properties.
A resin composition containing polyphenylene sulfide (PPS) and a polyphenylene ether (PPE) has been proposed for a hard disk drive arm or a hard disk drive carriage as optical parts (see JP-A-2004-75881, for example). However, the polyphenylene ether contained in the resin composition is a modified polyphenylene ether. Moreover, the document is silent about residual volatile components, low outgassing properties, and repeated removability.
A resin composition containing a polyester thermotropic liquid crystal polymer and inorganic particles has been proposed for hard disk drive centering hub parts (see JP-A-8-59965, for example). However, the document does not disclose a specific polyphenylene ether alloy and is silent about residual volatile components, low outgassing properties, low ionic contamination properties, and repeated removability.
A resin composition has been proposed which contains an alloy of polyethylene terephthalate (PET) or a polyamide with a liquid crystal polymer (see JP-A-11-263829, for example). However, the document does not disclose a specific polyphenylene ether alloy. Moreover, the document merely refers to HDD components and does not disclose specific HDD inner parts, residual volatile components, low outgassing properties, low ionic contamination properties, and repeated removability of a polyphenylene ether.
A thermoplastic resin has been proposed for antistatic members for disks and magnetic heads of hard disk drives (see JP-A-2002-275276, for example). However, the document substantially discloses a polycarbonate resin and does not disclose a specific polyphenylene ether alloy. Moreover, the document is silent about residual volatile components, low outgassing properties, low ionic contamination properties, and repeated removability.
Use of a modified polyphenylene ether for a base (housing) of hard disk drives has been proposed (see JP-A-3-280271, for example). However, the document does not disclose residual volatile components of the polyphenylene ether, low outgassing properties, low ionic contamination properties, and repeated removability.
Use of a composition containing a crystalline resin and an amorphous resin has been proposed for a transfer tray or a housing for hard disk drive parts (see JP-A-2005-290328, for example). However, the document does not disclose a specific polyphenylene ether composition and is silent about residual volatile components of the polyphenylene ether, low outgassing properties, low ionic contamination properties, and repeated removability.